The first preparation of 4-substituted 1,2-oxaborol-2(5H)-ols and their palladium-catalyzed cross-coupling with aryl halides to prepare stereodefined 2,3-disubstituted allyl alcohols

Article abstract of DOI:10.1055/s-2006-926388

4-Substituted 1,2-oxaborol-2(5H)-ols were prepared through copper-catalyzed carbomagnesation of propargyl alcohol, followed by the transmetallation of magnesium to boron in a one-pot procedure. The Suzuki-Miyaura cross-coupling of these new 2,2-disubstitu

Full text of DOI:10.1055/s-2006-926388

1148
PAPER
The First Preparation of 4-Substituted 1,2-Oxaborol-2(5H)-ols and their
Palladium-Catalyzed Cross-Coupling with Aryl Halides to Prepare
Stereodefined 2,3-Disubstituted Allyl Alcohols
P
reparation of 4-S
u
ubstitute
d
1,2
o
-Oxaborol-2
-
(5
H
)-olsHua Fang, Zheng-Jun Yan, Jun Yang, Min-Zhi Deng*
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Graduate School of the Chinese Academy of
Sciences, 354 Fenglin Lu, Shanghai 200032, P. R. of China
Fax +86(21)64166128; E-mail: dengmz@mail.sioc.ac.cn
Received 30 September 2005; revised 8 November 2005
reodefined substituted alkenylboronic acids are still re-
Abstract: 4-Substituted 1,2-oxaborol-2(5H)-ols were prepared
quired.
through copper-catalyzed carbomagnesation of propargyl alcohol,
followed by the transmetallation of magnesium to boron in a one-
pot procedure. The Suzuki–Miyaura cross-coupling of these new
2,2-disubstituted alkenylboronic acids with aryl halides afforded
stereodefined 2,3-disubstituted allyl alcohols in good to excellent
yields.
Stereodefined trisubstituted alkenes exist widely in both
natural and non-natural products,4 but their synthesis is
still a challenging problem in synthetic organic chemis-
try.5 Both trisubstituted alkenes and disubstituted allyl al-
cohols are also important intermediates in organic
synthesis which can, for example, be hydrogenated6 or
isomerized to aldehydes7 enantioselectively. Substituted
allyl alcohols are usually prepared by the Reformatsky re-
action of the corresponding ketone8 or by a Horner–Wad-
sworth–Emmons reaction,9 but a mixture of isomers is
often obtained.7,9 It was reported that stereodefined 3,3-
disubstituted allyl alcohols were obtained through the pal-
ladium-catalyzed cross-coupling of 3-hydroxypro-
penylstannane10a (Scheme 2) or -aluminum5b (Scheme 3)
with electrophiles; while 2,3-disubstituted allyl alcohols
were available through the copper-catalyzed carbomagne-
sation of 3-substituted propargyl alcohols, followed by
hydrolysis of the alkenylmagnesium intermediates
(Scheme 4).10b
Key words: alkenylboronic acids, copper-catalyzed carbomagne-
sation, Suzuki–Miyaura cross-coupling, stereodefined trisubstituted
alkenes, disubstituted allyl alcohols
Organoboron reagents, more specifically, alkenylboron
compounds (acids, esters, salts, etc.), play an important
role in organic transformations and synthesis.1 In most
cases, monosubstituted trans- and cis-alkenylboron com-
pounds were applied to the Suzuki–Miyaura cross-cou-
pling reaction because they were relatively easily
available through the hydroboration of alkynes or by other
means.2 There are only a few examples of the synthesis of
stereodefined disubstituted alkenylboron compounds
(Scheme 1),3 thus, new methods for the preparation of ste-
1) Cp2ZrHCl,
R'X, CuCN
1) n-BuLi
2) B(Oi-Pr)3
R'
Oi-Pr
Oi-Pr
R
H
R
B
2) H2O
3) HCl
R
B(OH)2
Scheme 1
R
R
R
R'2HCO
1) LiAlH4
2) ketone
R''3SnOMe
R'''X
[Pd]
R
Li
Al
R'''
R''3Sn
O
OH
R'2HCO
HO
HO
Scheme 2
Scheme 3
R
R
1) LiAlH4
2) ketone
R'2HCO
Li
R'2HCO
R''X
[Pd]
R
Al
O
OH
R''
OH
SYNTHESIS 2006, No. 7, pp 1148–1154
x
x
.
x
x
.2
0
0
6
Advanced online publication: 08.03.2006
DOI: 10.1055/s-2006-926388; Art ID: F16605SS
© Georg Thieme Verlag Stuttgart · New York

PAPER
Preparation of 4-Substituted 1,2-Oxaborol-2(5H)-ols
1149
Table 1 A New Series of 2,2-Disubstituted Alkenylboronic Acids
R
3a
R'
R
R'
H2O
R'MgX
Cu(I)
R
Mg
OH
O
OH
R
R
RMgX
Cu(I)
1) B(Oi-Pr)3
2) H3O+
Mg
HO
B
O
O
Scheme 4
OH
1
3
2
Herein, we wish to report the synthesis of a new series of
stereodefined 2,2-disubstituted alkenylboron acids via
copper-catalyzed carbomagnesation of propargyl alcohol,
followed by transmetallation from magnesium to boron,
and their palladium-catalyzed coupling with aryl halides
to give stereodefined 2,3-disubstituted allyl alcohols
(Scheme 5) which have a different configuration than that
obtained via the route showed in Scheme 4.
Our starting point was a report10 on the catalytic addition
(CuI, 10%; below –10 °C) of organomagnesium reagents
to the triple bond of propargyl alcohol, which afforded in-
termediate 2 (Scheme 5). After some modifications, such
as using 2.2 equivalents of Grignard reagents and THF in
place of diethyl ether as solvent, the intermediate 2 was
obtained, and in situ reaction with triisopropyl borate be-
low –60 °C gave the desired products 3 after hydrolysis in
moderate yields (Table 1).
Entry
R
Products
Yieldb (%)
64, 73c
70
1
2
3
4
5
6
7
Ph
3a
3b
3c
3d
3e
3f
Et
n-Pr
n-Bu
i-Pr
67
70
40
(CH2)2Ph
63, 59d
73
i-Bu
3g
a Reagents: Grignard reagent (220 mmol), propargyl alcohol (100
mmol).
b Isolated yields based on propargyl alcohol.
c Propargyl alcohol (1.0 equiv).
d BuLi (1.0 equiv) used instead of Grignard reagent (1.0 equiv).
We attempted the reaction with one equivalent of BuLi in-
stead of one equivalent of Grignard reagent to form the
lithium salt of propargyl alcohol; subsequent addition of
1.2 equivalents of Grignard reagent gave the same desired
compounds 3 after usual workup (Scheme 6). The struc-
tures of alkenylboronic acids 3 were confirmed by 1H–1H
NOESY, HRMS (EI), and other spectral analyses.
and 2), the cross-coupling reactions of 2,2-disubstituted
alkenylboronic acid with aryl bromide proceeded smooth-
ly in moderate yields. Using 2-(di-tert-butylphosphino)bi-
phenyl as ligand the cross-coupling reaction of 2,2-
disubstituted alkenylboronic acids with aryl bromides
proceeded at room temperature in high yield (Table 2, en-
try 3). None of the desired cross-coupling product was ob-
tained under the standard conditions with aryl chloride as
the electrophile, in fact, aryl chloride was recovered from
the reaction mixture (Table 2, entry 4). The cross-cou-
pling reaction of arylboronic acid and aryl chloride at
room temperature12a was studied, but did not result in the
corresponding product (Table 2, entry 6). With 2-(dicy-
clohexylphosphino)biphenyl as ligand, toluene as solvent,
and raising the reaction temperature to 100 °C, the cross-
coupling product formed in satisfying yield (Table 2, en-
try 5).
The Suzuki–Miyaura cross-coupling reaction has become
a powerful method for the formation of carbon–carbon
bonds,1a,1b,11 furthermore milder reaction conditions can
be used with bulky phosphorous ligands12a–c or other types
of ligands.12d After obtaining the new series of 2,2-disub-
stituted alkenylboronic acids, we investigated their palla-
dium-catalyzed cross-coupling reactions with aryl halides
especially with aryl chlorides using Buchwald’s phospho-
rous ligands. The optimum conditions for the coupling of
2,2-disubstituted alkenylboronic acids with aryl halides
were studied using 3b as an example (Table 2). Under
standard Suzuki–Miyaura conditions (Table 2, entries 1
R
HO
R
RMgX
Cu(I)
1) B(Oi-Pr)3
2) H3O+
ArX
B
Mg
[Pd]
O
O
OH
Ar
R
HO
1
2
4
3
Scheme 5
Scheme 6
OH
1) 1.2 equiv RMgX
1.0 equiv BuLi
OH
B
R
2) B(Oi-Pr)3
3) H3O+
O
OLi
1
3
Synthesis 2006, No. 7, 1148–1154 © Thieme Stuttgart · New York

1150
G.-H. Fang et al.
PAPER
Table 2 Coupling of 3b with Bromo- or Chlorobenzenea
C6H5X
HO B
[Pd]
C6H5
OH
O
3b
4e
Entry
Aryl halide
PhBr
Reaction conditions
Yieldb (%)
1
2
3
4
5
6
PdCl2(PPh3)2 (3 mol%), K3PO4·3H2O, toluene, 100 °C
PdCl2 (PPh3)2 (3 mol%), K2CO3, THF, reflux
77
73
86
–
PhBr
PhBr
Pd(OAc)2 (2 mol%), Ligand I (4 mol%),c KF·2H2O, THF, ambient temperature
PdCl2(PPh3)2 (3 mol%), K3PO4·3H2O, toluene, 100 °C
Pd(OAc)2 (2 mol%), Ligand II (4 mol%),c K3PO4·3H2O, toluene, 100 °C
Pd(OAc)2 (2 mol%), Ligand I (4 mol%),c KF·2H2O, THF, ambient temperature
PhCl
PhCl
83
–
PhCl
a Reagents: 3b (1.0 equiv), PhX (1.2 equiv), base (3.0 equiv), solvent (4.0 mL).
b Isolated yields based on the boronic acids used.
c Ligand I is 2-(di-tert-butylphosphino)biphenyl; Ligand II is 2-(dicyclohexylphosphino)biphenyl.
Ha
Hb
The optimized conditions (Table 2, entry 3 for aryl bro-
mides and entry 5 for aryl chlorides) were subsequently
applied to the coupling reactions of other substrates
(Table 3). The cross-coupling reaction of various 2,2-dis-
ubstituted alkenylboronic acids with aryl bromides or aryl
chlorides proceeded in good to excellent yields.
HO
B
O
Hc
OH
O
3b
4a
Figure 1
Table 3 Cross-Coupling of 2,2-Disubstituted Alkenylboronic Acids 3 with Aryl Halidesa
R
R
ArX
HO
B
Ar
OH
[Pd]
O
3
4
Entry
1
Boronic acids 3
ArX
Products 4
Yield (%)b
O
3b
86
Et
(A)
OH
Cl
O
4a
2
3
4
3a
3d
3d
89
(A)
Ph
O
O
OH
O
Cl
4b
83
(A)
Bu
OH
Cl
Cl
O
4c
80
(B)
F3C
Bu
F3C
OH
4d
Synthesis 2006, No. 7, 1148–1154 © Thieme Stuttgart · New York

PAPER
Preparation of 4-Substituted 1,2-Oxaborol-2(5H)-ols
1151
Table 3 Cross-Coupling of 2,2-Disubstituted Alkenylboronic Acids 3 with Aryl Halidesa (continued)
R
R
ArX
HO
B
Ar
OH
[Pd]
O
3
4
Entry
5
Boronic acids 3
ArX
Products 4
Yield (%)b
3b
83
Et
(B)
Cl
OH
4e
6
7
3d
3b
87
(A)
CF3
Bu
F3C
OH
F3C
F3C
Br
Cl
CF3
4f
85
(B)
Et
F3C
OH
4g
8
9
3b
3b
84
(A)
Et
Br
Cl
Cl
OH
4h
79
(A)
COOMe
Br
Et
MeOOC
OH
4i
a Reagents: boronic acid (1.0 equiv), aryl halide (1.2 equiv), of Pd(OAc)2 (2 mol%), ligand (4 mol%), base (3.0 equiv), solvent (4.0 mL/mmol),
20 h.
b Isolated yields based on the boronic acids used. A: 2-(di-tert-butylphosphino)biphenyl as ligand, KF·2H2O, THF, ambient temperature;
B: 2-(dicyclohexylphosphino)biphenyl as ligand, K3PO4·3H2O, toluene, 100 °C, 20 h.
In the 1H–1H NOESY spectrum of 4a, proton Ha (d = 6.42
were obtained from commercial sources and used in reactions with-
ppm) showed a strong NOE interaction with Hb (d = 2.42–
out further purification. THF was distilled from sodium benzophe-
1
none ketyl. H NMR spectra were recorded in CDCl3 on a Varian
2.35 ppm) with no interaction between Ha and Hc
300 MHz spectrometer. IR spectra were obtained using a Perkin-
(d = 4.29 ppm). The 2D-NOESY spectrum of 4a showed
Elmer 983 instrument. Mass spectra were obtained using a HP
that the product had the same configuration as 3b
(Figure 1). In the cross-coupling reaction, the configura-
5989A mass spectrometer.
tion of the double bond was retained.
4-Substituted 1,2-Oxaborol-2(5H)-ols 3a–g; General Procedure
Grignard reagent (220 mmol, 2.2 equiv) in THF (130 mL) was add-
ed dropwise to a solution of propargyl alcohol (100 mmol, 1.0
equiv) and CuI (1.9 g, 0.1 equiv) in THF (70 mL) under a N2 atmo-
sphere at –10 °C; during addition the reaction temperature was
maintained below –10 °C. After addition of the Grignard reagent,
the mixture was stirred for another 20 h at ambient temperature.
B(Oi-Pr)3 (120 mmol, 1.2 equiv) was added dropwise to the reaction
mixture at –60 °C. After the addition of borate, the temperature was
allowed to rise spontaneously to r.t. To the mixture, HCl (2 N; 230
mL) was added, then the resulting mixture was filtered, extracted
with EtOAc (3 × 50 mL), and dried over MgSO4. The crude product,
obtained after evaporation of the solvent, was dissolved in Et2O (2
mL per 1 mmol of product), the solution was extracted with an aq
solution of NaOH (8 N; 3–4 × 15 mL). The combined base solution
was washed with Et2O (2 × 30 mL) to remove any hydrophobic res-
idues and then acidified with HCl (6 N, 90 mL). The water phase
was extracted with Et2O (3 × 10 mL). The combined organic phase
was dried and the solvent was evaporated to give the desired com-
In conclusion, we have described the first stereodefined
preparation of 4-substituted 1,2-oxaborol-2(5H)-ols, a
new series of disubstituted alkenylboronic acids. The Su-
zuki–Miyaura type reaction of the stereodefined orga-
noborons with various haloarenes including unactivated
aryl chlorides proceeded well under modified conditions
to obtain the corresponding stereodefined 2,3-disubstitut-
ed alkenes in good to excellent yields. Haloarenes substi-
tuted with various functional groups are tolerated, thus,
we have described an efficient method for the preparation
of stereodefined 2,3-disubstituted allyl alcohols.
All reactions were carried out under argon unless otherwise noted.
B(Oi-Pr)3, Et2O, EtOAc, toluene, aryl chlorides and aryl bromides,
CuI, propargyl alcohol, Pd(OAc)2, phosphorous ligand 2-(di-tert-
butylphosphino) biphenyl and 2-(dicyclohexylphosphino)biphenyl
Synthesis 2006, No. 7, 1148–1154 © Thieme Stuttgart · New York

1152
G.-H. Fang et al.
PAPER
pounds 3a–g. Substrates 3a–g obtained by this procedure can be
used for cross-coupling without further purification.
4-Phenethyl-1,2-oxaborol-2(5H)-ol (3f)
White solid.
IR (KBr): 3325, 3028, 2937, 1605, 1457, 1485, 1430, 1246 cm–1.
1H NMR (300 MHz, CDCl3–D2O): d = 7.31–7.19 (m, 5 H), 5.60 (s,
1 H), 4.43 (s, 1 H), 2.87 (t, J = 8.0 Hz, 2 H), 2.58 (t, J = 8.0 Hz, 2 H).
13C NMR (75.5 Hz, CDCl3–D2O): d = 171.7, 141.0, 128.4, 126.0,
116.9, 74.3, 33.8, 32.2.
4-Phenyl-1,2-oxaborol-2(5H)-ol (3a)
White solid.
IR (KBr): 3359, 3030, 2932, 1570, 1497, 1464, 1424, 1228 cm–1.
1H NMR (300 MHz, CDCl3–D2O): d = 7.51–7.37 (m, 5 H), 6.22 (s,
1 H), 4.99 (s, 2 H).
13C NMR (75.5 Hz, CDCl3–D2O): d = 166.6, 133.5, 129.4, 128.7,
125.5, 116.2, 72.5.
MS (EI): m/z (%) = 188 (11), 128 (5), 97 (34), 96 (10), 92 (8), 91
(100), 53 (5).
HRMS (EI): m/z calcd for C11H13BO2, 188.1009; found, 188.1019.
MS (EI): m/z (%) = 160 (88), 159 (66), 131 (19), 129 (20), 116 (77),
115 (100), 77 (16), 69 (36).
4-Isobutyl-1,2-oxaborol-2(5H)-ol (3g)
HRMS (EI): m/z calcd for C9H9BO2, 160.0695; found, 160.0715.
Colorless liquid.
IR (liquid film): 3385, 2958, 1601, 1457, 1418, 1230, 1017 cm–1.
1H NMR (300 MHz, CDCl3–D2O): d = 5.49 (s, 1 H), 4.42 (s, 2 H),
2.14 (d, J = 7.5 Hz, 2 H), 1.80 (m, 1 H), 0.90 (d, J = 6.3 Hz, 6 H).
4-Ethyl-1,2-oxaborol-2(5H)-ol (3b)
Colorless liquid.
IR (liquid film): 3392, 2971, 1602, 1459, 1412, 1197 cm–1.
1H NMR (300 MHz, CDCl3–D2O): d = 5.52 (s, 1 H), 4.46 (s, 2 H),
2.26 (q, J = 7.5 Hz, 2 H), 1.13 (t, J = 7.5 Hz, 3 H).
13C NMR (75.5 Hz, CDCl3–D2O): d = 172.0, 74.5, 40.2, 27.3, 22.5.
MS (EI): m/z (%) = 98 (45), 97 (100), 96 (30), 81 (17), 54 (46), 53
(22), 43 (42), 41 (33).
13C NMR (75.5 Hz, CDCl3–D2O): d = 174.4, 115.6, 74.4, 23.8, 12.0.
HRMS (EI): m/z calcd for C7H13BO2, 140.1009; found, 140.0998.
MS (EI): m/z (%) = 112 (35), 97 (93), 96 (26), 83 (74), 68 (100), 67
(64), 53 (55).
Cross-Coupling Reaction of 4-Substituted 1,2-Oxaborol-2(5H)-
ols 3 with Aryl Halides; General Procedure
HRMS (EI): m/z calcd for C4H6BO2 [M+ – CH3], 97.0461; found,
97.0459.
4-Substituted 1,2-oxaborol-2(5H)-ols (3; 1.0 mmol), aryl halide
(1.2 mmol), base (3.0 mmol), Pd(OAc)2 (0.02 mmol, 4.5 mg), phos-
phorous ligand (0.04 mmol), and solvent (4.0 mL) were added to a
Schlenk flask under a N2 atmosphere. The reaction mixture was
stirred for 20 h at ambient temperature for aryl bromide or at 100 °C
for aryl chloride. After the usual workup, the crude products were
purified by flash chromatography on silica gel (n-hexane–EtOAc)
to afford the desired products 4a–i.
4-Propyl-1,2-oxaborol-2(5H)-ol (3c)
Colorless liquid.
IR (liquid film): 3333, 2930, 1601, 1427, 1379, 1203 cm–1.
1H NMR (300 MHz, CDCl3–D2O): d = 5.52 (s, 1 H), 4.45 (s, 2 H),
2.25 (t, J = 7.6 Hz, 2 H), 1.57 (m, 2 H), 0.95 (t, J = 7.5 Hz, 3 H).
13C NMR (75.5 Hz, CDCl3–D2O): d = 72.3, 116.3, 73.9, 32.4, 20.6,
13.5.
(Z)-1-{4-[2-(Hydroxymethyl)-1-butenyl]phenyl}-1-ethanone
(4a)
Pale yellow solid.
IR (KBr): 3428, 2966, 1681, 1409, 1272 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.88 (d, J = 8.7 Hz, 2 H), 7.33 (d,
J = 8.7 Hz, 2 H), 6.42 (s, 1 H), 4.29 (s, 2 H), 2.57 (s, 3 H), 2.38 (m,
2 H), 1.17 (t, J = 7.4 Hz, 3 H).
MS (EI): m/z (%) = 126 (16), 98 (17), 97 (100), 96 (28), 83 (24), 67
(28), 53 (27), 41 (14).
HRMS (EI): m/z calcd for C6H11BO2, 126.0852; found, 126.0858.
4-Butyl-1,2-oxaborol-2(5H)-ol (3d)
Colorless liquid.
13C NMR (75.5 Hz, CDCl3): d = 198.2, 145.4, 142.4, 134.6, 128.7,
IR (liquid film): 3383, 2932, 1602, 1458, 1415, 1240 cm–1.
128.0, 125.5, 60.2, 28.0, 26.3, 12.3.
1H NMR (300 MHz, CDCl3–D2O): d = 5.52 (s, 1 H), 4.45 (s, 2 H),
2.26 (t, J = 7.6 Hz, 2 H), 1.51 (m, 2 H), 1.34 (m, 2 H), 0.91 (t, J =
7.2 Hz, 3 H).
MS (EI): m/z (%) = 204 (57), 189 (100), 175 (63), 147 (44), 133
(43), 128 (39), 115 (74), 43 (67).
13C NMR (75.5 Hz, CDCl3–D2O): d = 172.6, 116.0, 74.0, 30.1, 29.5,
HRMS (EI): m/z calcd for C13H16O2, 204.1150; found, 204.1140.
22.2, 13.6.
(Z)-1-{4-[2-(Hydroxymethyl)-1-styryl]phenyl}-1-ethanone (4b)
White solid.
IR (KBr): 3511, 1669, 1600, 1490, 1268 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.99 (d, J = 8.1 Hz, 2 H), 7.63–
7.37 (m, 7 H), 6.99 (s, 1 H), 4.72 (s, 2 H), 2.64 (s, 3 H).
13C NMR (75.5 Hz, CDCl3): d = 197.7, 142.0, 141.7, 140.1, 135.6,
130.1, 129.1, 128.7, 128.4, 128.0, 126.6, 60.2, 26.6 ppm.
MS (EI): m/z (%) = 98 (27), 97 (100), 96 (61), 81 (29), 67 (27), 54
(52), 53 (43), 41 (44).
HRMS (EI): m/z calcd for C7H13BO2, 140.1009; found, 140.0988.
4-Isopropyl-1,2-oxaborol-2(5H)-ol (3e)
Colorless liquid.
IR (liquid film): 3437, 2967, 1596, 1457, 1415, 1267 cm–1.
1H NMR (300 MHz, CDCl3–D2O): d = 5.51 (s, 1 H), 4.53 (s, 2 H),
2.53 (m, 1 H), 1.14 (d, J = 6.2 Hz, 6 H).
MS (EI): m/z (%) = 253 (20), 252 (100), 237 (26), 178 (20), 147
(32), 105 (71), 91 (32), 43 (41).
13C NMR (75.5 Hz, CDCl3–D2O): d = 178.6, 114.4, 72.9, 30.0, 21.4.
HRMS (EI): m/z calcd for C17H16O2, 252.1150; found, 252.11504.
MS (EI): m/z (%) = 111 (54), 84 (32), 83 (34), 82 (95), 67 (100), 53
(37), 43 (62), 41 (45).
(Z)-1-{4-[2-(Hydroxymethyl)-1-hexenyl]phenyl}-1-ethanone
(4c)
White solid.
HRMS (EI): m/z calcd for C6H11BO2, 126.0852; found, 126.0840.
Synthesis 2006, No. 7, 1148–1154 © Thieme Stuttgart · New York

PAPER
Preparation of 4-Substituted 1,2-Oxaborol-2(5H)-ols
1153
IR (KBr): 3427, 1683, 1602, 1466, 1269, 1016 cm–1.
13C NMR (75.5 Hz, CDCl3): d = 145.5, 141.2, 128.7, 125.2, 125.1,
125.06, 125.0, 123.2, 66.0, 21.7, 12.9.
1H NMR (300 MHz, CDCl3): d = 7.92 (d, J = 7.6 Hz, 2 H), 7.33 (d,
J = 7.6 Hz, 2 H), 6.47 (s, 1 H), 4.28 (s, 2 H), 2.60 (s, 3 H), 2.34 (t,
J = 7.6 Hz, 2 H), 1.59 (m, 2 H), 1.41 (m, 2 H), 0.93 (t, J = 7.2 Hz,
3 H).
13C NMR (75.5 Hz, CDCl3): d = 198.0, 144.2, 142.3, 134.3, 134.7,
128.7, 128.2, 126.7, 60.3, 35.1, 30.1, 26.4, 22.4, 13.9.
19F NMR (282.3 MHz, CDCl3): d = 62.86.
MS (EI): m/z (%) = 230 (30), 214 (15), 213 (100), 211 (14), 201
(46), 173 (18), 159 (20), 57 (27).
HRMS (EI): m/z calcd for C12H13F3O, 230.0918; found, 230.0920.
MS (EI): m/z (%) = 175 (13), 129 (8), 133 (13), 115 (26), 105 (9),
(Z)-2-[2-Ethyl-3-(4-chlorophenyl)]-2-propen-1-ol (4h)
91 (11), 57 (12), 43 (100).
Colorless liquid.
HRMS (EI): m/z calcd for C15H20O2, 232.1463; found, 232.1505.
IR (KBr): 3336, 1594, 1328, 1014 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.29 (d, J = 8.4 Hz, 2 H), 7.18 (d,
J = 8.4 Hz, 2 H), 6.39 (s, 1 H), 4.25 (s, 2 H), 2.34 (q, J = 7.4 Hz, 2
H), 1.16 (t, J = 7.4 Hz, 3 H).
13C NMR (75.5 Hz, CDCl3): d = 143.5, 135.7, 132.4, 130.0, 128.3,
126.1, 60.9, 28.3, 12.7.
(Z)-2-{2-Butyl-3-[4-(trifluoromethyl)phenyl]}-2-propen-1-ol
(4d)
Colorless liquid.
IR (KBr): 3325, 1617, 1468, 1018 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.56 (d, J = 8.7 Hz, 2 H), 7.33 (d,
J = 8.7 Hz, 2 H), 6.45 (s, 1 H), 4.24 (s, 2 H), 2.15 (t, J = 7.7 Hz, 2
H), 1.55 (m, 2 H), 1.41 (m, 2 H), 0.95 (t, 3 H, J = 7.4 Hz).
13C NMR (75.5 Hz, CDCl3): d = 144.4, 128.8, 125.4, 125.0, 123.5,
123.2, 66.5, 30.5, 28.5, 22.8, 13.8.
MS (EI): m/z (%) = 196 (46), 179 (37), 167 (100), 128 (35), 127
(39), 125 (68), 115 (40), 55 (35).
HRMS (EI): m/z calcd for C11H13ClO, 196.0462; found, 196.0470.
Methyl (Z)-1-{2-[2-(Hydroxymethyl)-1-butenyl]}benzoate (4i)
Colorless liquid.
19F NMR (282.3 MHz, CDCl3): d = 13.5.
MS (EI): m/z (%) = 258 (43), 241 (67), 216 (57), 201 (100), 159
IR (KBr): 3421, 1724, 1569, 1259, 1016 cm–1.
(45), 85 (61), 57 (47), 41 (51).
1H NMR (300 MHz, CDCl3): d = 7.91 (m, 1 H), 7.46 (m, 1 H), 7.28
(m, 2 H), 6.73 (s, 1 H), 4.07 (s, 2 H), 3.86 (s, 3 H), 2.37 (q, J = 7.5
Hz, 2 H), 1.19 (t, J = 7.5 Hz, 3 H).
HRMS (EI): m/z calcd for C14H17F3O, 258.1231; found, 258.1236.
(Z)-2-[2-Ethyl-3-phenyl]-2-propen-1-ol (4e)
Colorless liquid.
IR (KBr): 3345, 1600, 1445, 1014 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.36–7.21 (m, 5 H), 6.45 (s, 1 H),
4.30 (s, 2 H), 2.35 (q, J = 7.5 Hz, 2 H), 1.17 (t, J = 7.5 Hz, 3 H).
13C NMR (75.5 Hz, CDCl3): d = 167.9, 142.3, 138.9, 131.7, 131.0,
130.3, 129.2, 126.7, 126.4, 61.1, 52.0, 27.4, 12.6.
MS (EI): m/z (%) = 220 (9), 189 (68), 160 (100), 159 (60), 145 (80),
143 (75), 131 (80), 128 (41).
HRMS (EI): m/z calcd for C13H16O3, 220.1100; found, 220.1101.
13C NMR (75.5 Hz, CDCl3): d = 142.8, 137.2, 128.6, 128.0, 126.9,
126.5, 60.7, 30.0, 12.6.
Acknowledgment
MS (EI): m/z (%) = 162 (36), 145 (100), 133 (50), 129 (16), 115
(25), 105 (22), 91 (37), 55 (15).
We thank the NNSF of China and State Key Laboratory of Organo-
metallic Chemistry, Shanghai Institute of Organic Chemistry, Chi-
nese Academy of Sciences, for financial support.
HRMS (EI): m/z calcd for C11H14O, 162.1045; found, 162.1074.
(Z)-2-{2-Butyl-3-[3,5-di(trifluoromethyl)phenyl]}-2-propen-1-
ol (4f)
Colorless liquid.
References
IR (KBr): 3330, 1649, 1467, 1019 cm–1.
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(s, 1 H), 4.24 (d, J = 4.7 Hz, 2 H), 2.38 (t, J = 7.6 Hz, 2 H), 1.58 (m,
4 H), 1.38 (m, 2 H), 0.97 (t, J = 7.2 Hz, 3 H).
13C NMR (75.5 Hz, CDCl3): d = 145.4, 139.2, 132.1, 131.7, 131.2,
130.8, 128.7, 128.6, 125.3, 125.17, 121.56, 120.30, 120.24, 120.19,
120.14, 120.09, 117.95, 60.17, 35.17, 30.15, 22.48, 13.78.
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MS (EI): m/z (%) = 310 (17), 309 (100), 308 (19), 85 (59), 57 (50),
55 (28), 43 (65), 41 (72).
cyclopropanation reactions: (i) Fontain, P.; Carboni, B.;
Vaultier, M.; Carie, R. Tetrahedron Lett. 1989, 30, 4815.
(j) Imai, T.; Maineta, H.; Nishida, S. J. Org. Chem. 1990, 55,
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N.; Lough, A. J. J. Am. Chem. Soc. 1999, 121, 450.
Ullmann reaction: (l) Chan, D. M. T.; Monaco, K. L.;
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(Z)-2-{2-Ethyl-3-[4-(trifluoromethyl)phenyl]}-2-propen-1-ol
(4g)
Colorless liquid.
IR (KBr): 3333, 1617, 1328, 1018.
1H NMR (300 MHz, CDCl3): d = 7.57 (d, J = 8.4 Hz, 2 H), 7.34 (d,
J = 8.4 Hz, 2 H), 6.54 (s, 1 H), 4.26 (s, 2 H), 2.59 (q, J = 7.5 Hz, 2
H), 1.10 (t, J = 7.5 Hz, 3 H).
Synthesis 2006, No. 7, 1148–1154 © Thieme Stuttgart · New York

1154
G.-H. Fang et al.
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